Tuesday, August 17, 2010


The dog (Canis lupus familiaris[1]) is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The domestic dog has been one of the most widely kept working, hunting and companion animals in human history.

The word "dog" may also mean the male of a canine species,[2] as opposed to the word "bitch" for the female of the species.[3]

The dog quickly became ubiquitous across world cultures, and was extremely valuable to early human settlements. For instance, it is believed that the successful emigration across the Bering Strait might not have been possible without sled dogs.[4] Dogs perform many roles for people, such as hunting, herding, protection, assisting police and military, companionship, and, more recently, aiding handicapped individuals. This versatility, more than almost any other known animal, has given them the nickname "Man's best friend" in the western world. Currently, there are estimated to be 400 million dogs in the world.[5]

Over the 15,000 year span that the dog had been domesticated, it diverged into only a handful of landraces, groups of similar animals whose morphology and behavior have been shaped by environmental factors and functional roles. As the modern understanding of genetics developed, humans began to intentionally breed dogs for a wide range of specific traits. Through this process, the dog has developed into hundreds of varied breeds, and shows more behavioral and morphological variation than any other land mammal.[6] For example, height measured to the withers ranges from a few inches in the Chihuahua to a few feet in the Irish Wolfhound; color varies from white through grays (usually called "blue'") to black, and browns from light (tan) to dark ("red" or "chocolate") in a wide variation of patterns; coats can be short or long, coarse-haired to wool-like, straight, curly, or smooth.[7] It is common for most breeds to shed this coat.

Etymology and related terminology

Dog is the common use term that refers to members of the subspecies Canis lupus familiaris. The term can also be used to refer to a wider range of related species, such as the members of the genus Canis, or "true dogs", including the Wolf, Coyote, and Jackals; or it can refer to the members of the subfamily Caninae, which would also include the African Wild Dog; or it can be used to refer to any member of the family Canidae, which would also include the Foxes, Bush dog, Racoon dog, and others.[8] Some members of the family have "dog" in their common names, such as the Raccoon Dog and the African Wild Dog. A few animals have "dog" in their common names but are not canids, such as the prairie dog.

The English word dog comes from Middle English dogge, from Old English docga, a "powerful dog breed".[9] The term may derive from Proto-Germanic *dukkōn, represented in Old English finger-docce ("finger-muscle").[10] The word also shows the familiar petname diminutive -ga also seen in frogga "frog", picga "pig", stagga "stag", wicga "beetle, worm", among others.[11] Due to the archaic structure of the word, the term dog may ultimately derive from the earliest layer of Proto-Indo-European vocabulary, reflecting the role of the dog as the earliest domesticated animal.[12]

In 14th century England, hound (from Old English: hund) was the general word for all domestic canines, and dog referred to a subtype of hound, a group including the mastiff. It is believed that this "dog" type of "hound" was so common that it eventually became the prototype of the category “hound”.[13] By the 16th century, dog had become the general word, and hound had begun to refer only to types used for hunting.[14] Hound, cognate to German Hund, Dutch hond, common Scandinavian hund, and Icelandic hundur, is ultimately derived from the Proto-Indo-European *kwon- "dog", found in Welsh ci (plural cwn), Latin canis, Greek kýōn, Lithuanian šuõ.[15]

In breeding circles, a male canine is referred to as a dog, while a female is called a bitch (Middle English bicche, from Old English bicce, ultimately from Old Norse bikkja). A group of offspring is a litter. The father of a litter is called the sire, and the mother is called the dam. Offspring are generally called pups or puppies, from French poupée, until they are about a year old. The process of birth is whelping, from the Old English word hwelp, (cf. German Welpe, Dutch welp, Swedish valp, Icelandic hvelpur) .[16]


The domestic dog was originally classified as Canis familiaris and Canis familiarus domesticus by Carolus Linnaeus in 1758,[17][18] and was reclassified in 1993 as Canis lupus familiaris, a subspecies of the gray wolf Canis lupus, by the Smithsonian Institution and the American Society of Mammalogists. Overwhelming evidence from behavior, vocalizations, morphology, and molecular biology led to the contemporary scientific understanding that a single species, the gray wolf, is the common ancestor for all breeds of domestic dogs;[4][19] however, the timeframe and mechanisms by which dogs diverged are controversial.[4] Canis lupus familiaris is listed as the name for the taxon that is broadly used in the scientific community and recommended by ITIS, however Canis familiaris is a recognised synomym.[20]

History and evolution

Main article: Origin of the domestic dog

A hunter with a large pack of beagles, a breed of hunting dogs, 1885.

Ancient Greek black-figure pottery depicting the return of a hunter and his dog. Made in Athens between 550-530 BC, found in Rhodes.

Riders and dogs. Ancient Greek Attic black-figure hydria, ca. 510–500 BC, from Vulci. Louvre Museum, Paris.Ancient Greek rhyton in the shape of a dog's head, made by Brygos, early 5th century BC. Jérôme Carcopino Museum, Department of Archaeology, Aleria

Domestic dogs inherited a complex social hierarchy and behaviors from their wolf ancestors. Dogs are pack animals with a complex set of behaviors related to determining each dog's position in the social hierarchy, and they exhibit various postures and other means of nonverbal communication that reveal their states of mind.[1] These sophisticated forms of social cognition and communication may account for their trainability, playfulness, and ability to fit into human households and social situations, and these attributes have earned dogs a unique relationship with humans despite being potentially dangerous apex predators.[4]

Although experts largely disagree over the details of dog domestication, it is agreed that human interaction played a significant role in shaping the subspecies.[4] Shortly after domestication, dogs became ubiquitous in human populations, and spread throughout the world. Emigrants from Siberia likely crossed the Bering Strait with dogs in their company, and some experts suggest that use of sled dogs may have been critical to the success of the waves that entered North America roughly 12,000 years ago. Dogs were an important part of life for the Athabascan population in North America, and were their only domesticated animal. Dogs also carried much of the load in the migration of the Apache and Navajo tribes 1,400 years ago. Use of dogs as pack animals in these cultures often persisted after the introduction of the horse to North America.[21]

The current consensus among biologists and archaeologists is that the dating of first domestication is indeterminate.[4][21] There is conclusive evidence that dogs genetically diverged from their wolf ancestors at least 15,000 years ago,[22][23][24] but some believe domestication to have occurred earlier.[4] It is not known whether humans domesticated the wolf as such to initiate dog's divergence from its ancestors, or whether dog's evolutionary path had already taken a different course prior to domestication. The latter view has gained proponents, such as biologists Raymond and Lorna Coppinger;[5] they theorize that some wolves gathered around the campsites of the paleolithical man to scavenge refuse, and that associated evolutionary pressure developed that favored those who were less frightened by, and keener in approaching, humans.

The bulk of the scientific evidence for the evolution of the domestic dog stems from archaeological findings and mitochondrial DNA studies. The divergence date of roughly 15000 years ago is based in part on archaeological evidence that demonstrates that the domestication of dogs occurred more than 15,000 years ago,[4][21] and some genetic evidence indicates that the domestication of dogs from their wolf ancestors began in the late Upper Paleolithic close to the Pleistocene/Holocene boundary, between 17,000 and 14,000 years ago.[25] But there is a wide range of other, contradictory findings that make this issue controversial.

Archaeological evidence suggests that the latest dogs could have diverged from wolves was roughly 15000 years ago, although it is possible that they diverged much earlier.[4] In 2008, a team of international scientists released findings from an excavation at Goyet Cave in Belgium declaring that a large, toothy canine existed 31,700 years ago and ate a diet of horse, musk ox and reindeer.[26] Prior to this Belgium discovery, the earliest dog fossils were two large skulls from Russia and a mandible from Germany, that dated from roughly 14,000 years ago.[4][24] Remains of smaller dogs from Natufian cave deposits in the Middle East, including the earliest burial of a human being with a domestic dog, have been dated to around 10,000 to 12,000 years ago.[24][27] There is a great deal of archaeological evidence for dogs throughout Europe and Asia around this period and through the next two thousand years (roughly 8,000 to 10,000 years ago), with fossils uncovered in Germany, the French Alps, and Iraq, and cave paintings in Turkey.[4]

This Roman mosaic shows a large dog with a collar hunting a lion.DNA studies have provided a wider range of possible divergence dates, from 15,000 to 40,000 years ago,[24] to as much as 100,000 to 140,000 years ago.[28] This evidence depends on a number of assumptions that may be violated.[4] Genetic studies are based on comparisons of genetic diversity between species, and depend on a calibration date. Some estimates of divergence dates from DNA evidence use an estimated wolf-coyote divergence date of roughly 700,000 years ago as a calibration.[29] If this estimate is incorrect, and the actual wolf-coyote divergence is closer to one or two million years ago, or more,[30] then the DNA evidence that supports specific dog-wolf divergence dates would be interpreted very differently. Furthermore, it is believed that the genetic diversity of wolves has been in decline for the last 200 years, and that the genetic diversity of dogs has been reduced by selective breeding. This could significantly bias DNA analyses to support an earlier divergence date. The genetic evidence for the domestication event occurring in East Asia is also subject to violations of assumptions. These conclusions are based on the location of maximal genetic divergence, and assume that hybridization does not occur, and that breeds remain geographically localized. Although these assumptions hold for many species, there is good reason to believe that they do not hold for canines.[4]

Genetic analyses indicate all dogs are likely descended from a handful of domestication events with a small number of founding females,[4][25] although there is evidence that domesticated dogs interbred with local populations of wild wolves on several occasions.[24] Data suggests that dogs first diverged from wolves in East Asia, and that these domesticated dogs then quickly migrated throughout the world, reaching the North American continent around 8000 B.C.[24] The oldest groups of dogs, which show the greatest genetic variability and are the most similar to their wolf ancestors, are primarily Asian and African breeds, including the Basenji, Lhasa Apso, and Siberian Husky.[31] Some breeds that were thought to be very old, such as the Pharaoh Hound, Ibizan Hound, and Norwegian Elkhound, are now known to have been created more recently.[31]

There is a great deal of controversy surrounding the evolutionary framework for the domestication of dogs.[4] Although it is widely claimed that "man domesticated the wolf,"[32] man may not have taken such a proactive role in the process.[4] The nature of the interaction between man and wolf that led to domestication is unknown and controversial. At least three early species of the Homo genus began spreading out of Africa roughly 400,000 years ago, and thus lived for a considerable period in contact with canine species. Despite this, there is no evidence of any adaptation of canine species to the presence of the close relatives of modern man. If dogs were domesticated, as believed, roughly 15,000 years ago, the event (or events) would have coincided with a large expansion in human territory and the development of agriculture. This has led some biologists to suggest that one of the forces that led to the domestication of dogs was a shift in human lifestyle in the form of established human settlements. Permanent settlements would have coincided with a greater amount of disposable food and would have created a barrier between wild and anthropogenic canine populations.[4]

Roles with humans

Early roles

Wolves, and their dog descendants, would have derived significant benefits from living in human camps—more safety, more reliable food, lesser caloric needs, and more chance to breed.[33] They would have benefited from humans’ upright gait that gives them larger range over which to see potential predators and prey, as well as color vision that, at least by day, gives humans better visual discrimination.[33] Camp dogs would also have benefitted from human tool use, as in bringing down larger prey and controlling fire for a range of purposes.[33]

Humans would also have derived enormous benefit from the dogs associated with their camps.[34] For instance, dogs would have improved sanitation by cleaning up human waste and food scraps.[34] Dogs may have provided warmth, as referred to in the Australian Aboriginal expression “three dog night”[clarification needed] and they would have alerted the camp to the presence of predators or strangers, using their acute hearing to provide an early warning.[34] Anthropologists believe the most significant benefit would have been the use of dogs' sensitive sense of smell to assist with the hunt.[34] The relationship between the presence of a dog and success in the hunt is often mentioned as a primary reason for the domestication of the wolf, and a 2004 study of hunter groups with and without a dog gives quantitative support to the hypothesis that the benefits of cooperative hunting was an important factor in wolf domestication.[35]

The cohabitation of dogs and humans would have greatly improved the chances of survival for early human groups, and the domestication of dogs may have been one of the key forces that led to modern humans.[36] Anthropologists Tacon and Pardoe argue that the effects of human-canine cohabitation on humans would have been profound, and hypothesize that some of the effects could have been moving from scavenging to large game hunting, the establishment and marking of territories, living in optimally sized social groups, hunting/working in synchronised teams, and negotiating partnership bonds.[34] The human-dog partnership set both species on a new evolutionary course.

A British Bulldog shares a day at the park.As pets

“The most widespread form of interspecies bonding occurs between humans and dogs” [34] and the keeping of dogs as companions, particularly by elites, has a long history.[37] However pet dog populations grew significantly after WWII as suburbanization increased.[37] In the 1950s and 1960s dogs were kept outside,[38] (using the expression “in the doghouse” to describe exclusion from the group signifies the distance between the doghouse and the home) and were still primarily functional, acting as a guard, children’s playmate, or walking companion.[38] From the 1980s we have seen significant changes in the role of the pet dog, and writer John Katz describes the new work of dogs as the emotional support of their owner.[39] People and dogs have become increasingly integrated and implicated in each other’s lives,[40] to the point where pet dogs actively shape the way that family and home are experienced.[41]

There have been two major trends in the changing status of pet dogs. The first has been the ‘commodification’ of the dog, shaping it to conform to human expectations of personality and behaviour.[41] The second has been the broadening of the concept of the family and the home to include dogs-as-dogs within everyday routines and practices.[41]

Social geographer Heidi Nast points out the vast range of commodity forms available to transform a pet dog into an ideal companion.[42] The list of goods, services and places available is enormous: from dog perfumes, couture, furniture and housing, to dog groomers, therapists, trainers and care-takers, dog cafes, spas, parks and beaches, and dog hotels, airlines and cemeteries.[42] While dog training as an organized activity can be traced back to the 1700s, in the last decades of the 20th Century it became a high profile issue as many normal dog behaviors such as barking, jumping up, digging, rolling in dung, fighting, and urine marking became increasingly incompatible with the new role of a pet dog.[43] Dog training books, classes and television programs proliferated as the process of commodifying the pet dog continued.[44]

A pet dog is part of the Christmas traditionsThe majority of contemporary dog owners describe their dog as part of the family,[41] although some ambivalence about the relationship is evident in the popular reconceptualisation of the dog-human family as a pack.[41] A dominance model of dog-human relationships has been promoted by some dog trainers such as on the television program Dog Whisperer, however it has been disputed that "trying to achieve status" is characteristic of dog–human interactions.[45] Pet dogs play an active role in family life, for example, a study of conversations in dog-human families showed how family members use the dog as a resource, talking to the dog, or talking through the dog, to mediate their interactions with each other.[46] Another study of dogs’ roles in families showed that many dogs have set tasks or routines undertaken as family members, the most common of which was helping with the washing-up by licking the plates in the dishwasher, and bringing in the newspaper from the lawn.[41] Increasingly, human family members are engaging in activities that are centred on the perceived needs and interests of the dog, or in which the dog is an integral partner such as Dog Dancing and Doga.[42]

According to the statistics published by the American Pet Products Manufacturers Association in the National Pet Owner Survey in 2009-2010, it is estimated that there are 77.5 million dogs owners in the United States.[47] Also, the same survey shows that nearly 40% of the American households own at least one dog, from which 67% own just one dog, 25% two dogs and nearly 9% more than two dogs. There does not seem to be any gender preference among dogs as pets, as the statistical data reveals an equal number of female dog pets and male dog pets. Yet, although several programs are undergoing to promote pet adoption, only nearly a fifth of the owned dogs come from a shelter.


Dogs have lived and worked with humans in so many roles that they have earned the unique nickname, "man's best friend",[48] a phrase which is used in other languages as well. They have been bred for herding livestock,[49] hunting (e.g. pointers and hounds),[50] rodent control,[1] guarding, helping fishermen with nets, and pulling loads, in addition to their roles as companions.[1]

Service dogs such as guide dogs, utility dogs, assistance dogs, hearing dogs, and psychological therapy dogs provide assistance to individuals with physical or mental disabilities.[51][52] Some dogs owned by epileptics have been shown to alert their handler when the handler shows signs of an impending seizure, sometimes well in advance of onset, allowing the owner to seek safety, medication, or medical care.[53]

Dogs that are included in human activities in terms of helping out humans are usually called working dogs. Dogs of several breeds are considered working dogs. The main working dog breeds include Akita, Alaskan Malamute, Anatolian Shepherd Dog, Bernese Mountain Dog, Black Russian Terrier, Boxer, Bullmastiff, Doberman Pinscher, Dogue de Bordeaux, German Pinscher, Giant Schnauzer, Great Dane, Great Pyrenees, Great Swiss Mountain Dog, Komondor, Kuvasz, Mastiff, Neapolitan Mastiff, Newfoundland, Portuguese Water Dog, Rottweiler, Saint Bernard, Samoyed, Siberian Husky, Standard Schnauzer, and Tibetan Mastiff.

Based on their size and strength these dogs are more suitable for a wide range of jobs rather than companions for average families.[54] Moreover, most of these dogs have a different type of personality, usually more aggressive which makes the relationship with their trainer safer when he is a professional and knows what type of behavior to expect from such a dog. The working dogs are trained properly and accordingly to the activities they will perform. Yet, despite the size of some dogs they are sometimes used as pets as well. However, they generally require special training and owners might have to learn how to bind with their pet, in these cases.

Some of these dogs are suitable for more than a single activity. For instance, Akita is a popular dog in the ring show but its qualities make it a reliable animal in therapy work. The Alaskan Malamute is one of the most powerful and strong working dogs and although some families have this type of breed as a pet, they are more likely to enjoy sledding, and performing different mountainous activities with their owners. The Anatolian Shepherd dog as well as the Black Russian Terrier is famous for their ability to work as guard dogs, being used to protect livestock. The Swiss Mountain dogs, Bullmastiffs and German Pinschers are suitable for carting, obedience, tracking and even therapy work.

Boxers are commonly used as service dogs for blind people because of their intelligence and alert expression. During war time, this type of dog was also used as a courier. Dobermans have proven themselves as great learners with an amazing capacity of retaining training and as a result they are commonly trained and used as police or war dogs. Some other types of breeds are easily trained for hunting or fighting such as the Dogue de Bordeaux.

Sports and shows

Owners of dogs often enter them in competitions[55] such as breed conformation shows or sports, including racing and sledding.

In conformation shows, also referred to as breed shows, a judge familiar with the specific dog breed evaluates individual purebred dogs for conformity with their established breed type as described in the breed standard. As the breed standard only deals with the externally observable qualities of the dog (such as appearance, movement, and temperament), separately tested qualities (such as ability or health) are not part of the judging in conformation shows.

As a food source

See also: Dog meat

Dog meat is consumed in some East Asian countries, including Korea, China, and Vietnam, a practice that dates back to antiquity.[56] It is estimated that 13–16 million dogs are killed and consumed in Asia every year.[57] The BBC claims that, in 1999, more than 6,000 restaurants served soups made from dog meat in South Korea.[58] In Korea, the primary dog breed raised for meat, the nureongi (누렁이), differs from those breeds raised for pets which Koreans may keep in their homes.[59] The most popular Korean dog dish is gaejang-guk (also called bosintang), a spicy stew meant to balance the body's heat during the summer months; followers of the custom claim this is done to ensure good health by balancing one's gi, or vital energy of the body. A 19th century version of gaejang-guk explains that the dish is prepared by boiling dog meat with scallions and chili powder. Variations of the dish contain chicken and bamboo shoots. While the dishes are still popular in Korea with a segment of the population, dog is not as widely consumed as beef, chicken, and pork.[60]

Other cultures, such as Polynesia and Pre-Columbian Mexico, also consumed dog meat in their history. However, Western, South Asian, African, and Middle Eastern cultures generally regard consumption of dog meat as taboo. In some places, however, such as in rural areas of Poland, dog fat is believed to have medicinal properties—being good for the lungs for instance.[61]

A CNN reportage in China dated March 2010 interviews a dog meat vendor who states that most of the dogs that are available for selling to restaurant are raised in special farms but that there is always a chance that a sold dog is someone's lost pet, although dog pet breeds are not considered edible.[62]

Health risks to humans

In the USA, cats and dogs are a factor in more than 86,000 falls each year.[63] It has been estimated that around 2% of dog related injuries treated in UK hospitals are domestic accidents. The same study found that while dog involvement in road traffic accidents were difficult to quantify, dog associated road accidents involving injury more commonly involved two-wheeled vehicles.[64]

Toxocara canis (dog roundworm) eggs in dog feces can cause toxocariasis. In the United States, about 10,000 cases of Toxocara infection are reported in humans each year and almost 14% of the US population is infected.[65] In Great Britain, 24% of soil samples taken from public parks contained Toxocara canis eggs.[66] Untreated toxocariasis can cause retinal damage and decreased vision.[66] Dog feces can also contain hookworms that cause cutaneous larva migrans in humans.[67][68][69][70]

The incidence of dog bites, and especially fatal dog bites, is extremely rare in America considering the number of pet dogs in the country.[71] Fatalities from dog bites occur in America at the rate of one per four million dogs.[71] A Colorado study found that bites in children were less severe than bites in adults.[72] The incidence of dog bites in the US is 12.9 per 10,000 inhabitants, but for boys aged 5 to 9 the incidence rate is 60.7 per 10,000. Moreover, children have a much higher chance to be bitten in the face or neck.[73] Sharp claws with powerful muscles behind them can lacerate flesh in a scratch that can lead to serious infections.[74]

In the UK between 2003 and 2004, there were 5,868 dog attacks on humans resulting in 5,770 working days lost in sick leave.[75]

Health benefits for humans

Small dog watching the camera.A growing body of research indicates that the companionship of a dog can enhance human physical health and psychological wellbeing.[76] Dog and cat owners have been shown to have better mental and physical health than non-owners, making fewer visits to the doctor and being less likely to be on medication than non-owners.[77] In one study new pet owners reported a highly significant reduction in minor health problems during the first month following pet acquisition, and this effect was sustained in dog owners through to the end of the study. In addition, dog owners took considerably more physical exercise than cat owners and non-pet owners. The group without pets exhibited no statistically significant changes in health or behaviour. The results provide evidence that pet acquisition may have positive effects on human health and behaviour, and that for dog owners these effects are relatively long term.[78] Pet ownership has also been associated with increased coronary artery disease survival, with dog owners being significantly less likely to die within one year of an acute myocardial infarction than those who did not own dogs.[79]

The health benefits of dogs can result from contact with dogs, not just from dog ownership. For example, when in the presence of a pet dog, people show reductions in cardiovascular, behavioral, and psychological indicators of anxiety.[80] The benefits of contact with a dog also include social support, as dogs are able to not only provide companionship and social support themselves, but also to act as facilitators of social interactions between humans.[81] One study indicated that wheelchair users experience more positive social interactions with strangers when they are accompanied by a dog than when they are not.[82]

The practice of using dogs and other animals as a part of therapy dates back to the late 18th century, when animals were introduced into mental institutions to help socialize patients with mental disorders.[83] Animal-assisted intervention research has shown that animal-assisted therapy with a dog can increase a person with Alzheimer’s disease’s social behaviours, such as smiling and laughing.[84] One study demonstrated that children with ADHD and conduct disorders who participated in an education program with dogs and other animals showed increased attendance, increased knowledge and skill objectives, and decreased antisocial and violent behavior compared to those who were not in an animal-assisted program.[85]


Main article: Animal shelter

Every year, between 6 and 8 million dogs and cats enter US animal shelters.[86] The Humane Society of the United States (HSUS) estimates that approximately 3 to 4 million dogs and cats are euthanized yearly in shelters across the United States.[87] However, the percentage of dogs in US animal shelters that are eventually adopted and removed from the shelters by their new owners has increased since the mid 1990s from around 25% up to around 60-75% in the mid 2000s.[88]

Pets entering the shelters are euthanized in countries all over the world because of the lack of financial provisions to take care of these animals. Most shelters complain of not having enough resources to feed the pets and by being constraint to kill them as the likelihood for all of them to find an owner is very small. In poor countries, euthanasia is usually violent.


Main article: Dog anatomy

Domestic dogs have been selectively bred for millennia for various behaviors, sensory capabilities, and physical attributes.[1] Modern dog breeds show more variation in size, appearance, and behavior than any other domestic animal. Nevertheless, their morphology is based on that of their wild ancestors, gray wolves.[1] Dogs are predators and scavengers, and like many other predatory mammals, the dog has powerful muscles, fused wrist bones, a cardiovascular system that supports both sprinting and endurance, and teeth for catching and tearing. Dogs are highly variable in height and weight. The smallest known adult dog was a Yorkshire Terrier, that stood only 6.3 centimetres (2.5 in) at the shoulder, 9.5 cm (3.7 in) in length along the head-and-body, and weighed only 113 grams (4.0 oz). The largest known dog was an English Mastiff which weighed 155.6 kilograms (343 lb) and was 250 cm (98 in) from the snout to the tail.[89] The tallest dog is a Great Dane that stands 106.7 cm (42.0 in) at the shoulder.[90]



A Greyhound, one of many breeds of sighthound.Like most mammals, dogs are dichromats and have color vision equivalent to red-green color blindness in humans (deuteranopia).[91][92][93][94]

The dog's visual system has evolved to aid proficient hunting.[91] While a dog's visual acuity is poor (that of a poodle's has been estimated to translate to a Snellen rating of 20/75[91]), their visual discrimination for moving objects is very high; dogs have been shown to be able to discriminate between humans (e.g. identifying their owner) from distances up to a mile.[91] As crepuscular hunters, dogs often rely on their vision in low light situations: they have very large pupils, a high density of rods in the fovea, an increased flicker rate, and a tapetum lucidum.[91] The tapetum is a reflective surface behind the retina that reflects light back to give the photoreceptors a second chance to catch the photons.

The eyes of different breeds of dogs have different shapes, dimensions, and retina configurations.[95] Many long-nosed breeds have a "visual streak" – a wide foveal region that runs across the width of the retina and gives them a very wide field of excellent vision. Some long-muzzled breeds, particularly the sighthounds, have a field of vision up to 270° (compared to 180° for humans). Short-nosed breeds, on the other hand, have an "area centralis": a central patch with up to three times the density of nerve endings as the visual streak, giving them detailed sight much more like a human's. Some broad-headed breeds with short noses have a field of vision similar to that of humans.[92][93] Most breeds have good vision, but some show a genetic predisposition for myopia – such as Rottweilers, where one out of every two has been found to be myopic.[91]


The frequency range of dog hearing is approximately 40 Hz to 60,000 Hz,[96] which means that dogs can detect sounds far beyond the upper limit of the human auditory spectrum.[93][96][97] Additionally, dogs have ear mobility which allows them to rapidly pinpoint the exact location of a sound.[98] Eighteen or more muscles can tilt, rotate, raise, or lower a dog's ear. A dog can identify a sound's location much faster than a human can, as well as hear sounds at four times the distance.[98]


The highly sensitive nose of a dog.While the human brain is dominated by a large visual cortex, the dog brain is dominated by an olfactory cortex.[91] The olfactory bulb in dogs is roughly forty times bigger than the olfactory bulb in humans, relative to total brain size, with 125 to 220 million smell-sensitive receptors.[91] The bloodhound exceeds this standard with nearly 300 million receptors.[91] Dogs can discriminate odors at concentrations nearly 100 million times lower than humans can.[99] The wet nose is essential for determining the direction of the air current containing the smell. Cold receptors in the skin are sensitive to the cooling of the skin by evaporation of the moisture by air currents.[100]

Physical characteristics


Main article: Coat (dog)

A heavy winter coat with countershading in a mixed breedThe coats of domestic dogs are of two varieties: "double" being common with dogs (as well as wolves) originating from colder climates, made up of a coarse guard hair and a soft down hair, or "single", with the topcoat only.

Domestic dogs often display the remnants of countershading, a common natural camouflage pattern. A countershaded animal will have dark coloring on its upper surfaces and light coloring below,[101] which reduces its general visibility. Thus many breeds will have an occasional "blaze", stripe, or "star" of white fur on their chest or underside.[102]


There are many different shapes for dog tails: straight, straight up, sickle, curled, or cork-screw. In some breeds, the tail is traditionally docked to avoid injuries (especially for hunting dogs).[103] In some breeds, puppies can be born with a short tail or no tail at all.[104] This occurs more frequently in those breeds that are frequently docked and thus have no breed standard regarding the tail.

Types and breeds

Main article: Dog breed

Further information: Dog type

Cavalier King Charles Spaniels demonstrate with-breed variation.While all dogs are genetically very similar,[24] natural selection and selective breeding have reinforced certain characteristics in certain populations of dogs, giving rise to dog types and dog breeds. Dog types are broad categories based on function, genetics, or characteristics.[105] Dog breeds are groups of animals that possess a set of inherited characteristics that distinguishes them from other animals within the same species. Modern dog breeds are non-scientific classifications of dogs kept by modern kennel clubs. Purebred dogs of one breed are genetically distinguishable from purebred dogs of other breeds,[31] but the means by which kennel clubs classify dogs is unsystematic. Systematic analyses of the dog genome has revealed only four major types of dogs that can be said to be statistically distinct.[31] These include the "old world dogs" (e.g., Malamute and Shar Pei), "Mastiff"-type (e.g., English Mastiff), "herding"-type (e.g., Border Collie), and "all others" (also called "modern"- or "hunting"-type).[31][106]


Main article: Dog health

Further information: Category:Dog health

See also: CVBD

Dogs are susceptible to various diseases, ailments, and poisons, some of which can affect humans. To defend against many common diseases, dogs are often vaccinated.

A mixed-breed dogSome breeds of dogs are prone to certain genetic ailments such as elbow or hip dysplasia, blindness, deafness, pulmonic stenosis, cleft palate, and trick knees. Two serious medical conditions particularly affecting dogs are pyometra, affecting unspayed females of all types and ages, and bloat, which affects the larger breeds or deep-chested dogs. Both of these are acute conditions, and can kill rapidly. Dogs are also susceptible to parasites such as fleas, ticks, and mites, as well as hookworm, tapeworm, roundworm, and heartworm.

Dogs are highly susceptible to theobromine poisoning, typically from ingestion of chocolate. Theobromine is toxic to dogs because although the dog's metabolism is capable of breaking down the chemical, the process is so slow that even small amounts of chocolate can be fatal, especially dark chocolate.

Dogs are also vulnerable to some of the same health conditions as humans, including diabetes, dental and heart disease, epilepsy, cancer, hypothyroidism, and arthritis.[107]


Main article: Aging in dogs

The typical lifespan of dogs varies widely among breeds, but for most the median longevity, the age at which half the dogs in a population have died and half are still alive, ranges from 10 to 13 years.[108][109][110][111] Individual dogs may live well beyond the median of their breed.

The breed with the shortest lifespan (among breeds for which there is a questionnaire survey with a reasonable sample size) is the Dogue de Bordeaux, with a median longevity of about 5.2 years, but several breeds, including Miniature Bull Terriers, Bloodhounds, and Irish Wolfhounds are nearly as short-lived, with median longevities of 6 to 7 years.[111]

The longest-lived breeds, including Toy Poodles, Japanese Spitz, Border Terriers, and Tibetan Spaniels, have median longevities of 14 to 15 years.[111] The median longevity of mixed breed dogs, taken as an average of all sizes, is one or more years longer than that of purebred dogs when all breeds are averaged.[109][110][111][112] The dog widely reported to be the longest-lived is "Bluey," who died in 1939 and was claimed to be 29.5 years old at the time of his death; however, the Bluey record is anecdotal and unverified.[113] The longest verified records are of dogs living for 24 years.[113]


Although wild dogs, like wolves, are apex predators, they can be killed in territory disputes with wild animals.[114] Furthermore, in areas where both dogs and other large predators live, dogs can be a major food source for big cats or canines. Reports from Croatia indicate that dogs are killed by wolves more frequently than sheep. Wolves in Russia apparently limit feral dog populations. In Wisconsin, more compensation has been paid for dog losses than livestock.[114] Some wolf pairs have been reported to prey on dogs by having one wolf lure the dog out into heavy brush where the second animal waits in ambush.[115] In some instances, wolves have displayed an uncharacteristic fearlessness of humans and buildings when attacking dogs, to the extent that they have to be beaten off or killed.[116] Coyotes and big cats have also been known to attack dogs. Leopards in particular are known to have a predilection for dogs, and have been recorded to kill and consume them regardless of the dog's size or ferocity.[117] Tigers in Manchuria, Indochina, Indonesia, and Malaysia, are reputed to kill dogs with the same vigor as leopards.[118] Striped Hyenas are major predators of village dogs in Turkmenistan, India, and the Caucasus.[119] Reptiles such as alligators and pythons have been known to kill and eat dogs.


See also: Dog food

Golden Retriever eating a pig's foot.Despite their descent from wolves and classification as Carnivora, dogs are variously described in scholarly and other writings as carnivores[120][121] or omnivores.[1][122][123][124] Unlike obligate carnivores, such as the cat family with its shorter small intestine, dogs can adapt to a wide-ranging diet, and are not dependent on meat-specific protein nor a very high level of protein in order to fulfill their basic dietary requirements. Dogs will healthily digest a variety of foods, including vegetables and grains, and can consume a large proportion of these in their diet.[1]

A number of common human foods and household ingestibles are toxic to dogs, including chocolate solids (theobromine poisoning), onion and garlic (thiosulphate, sulfoxide or disulfide poisoning),[125] grapes and raisins, macadamia nuts, as well as various plants and other potentially ingested materials.[126][127]


Two dogs copulating on a beachMain article: Canine reproduction

In domestic dogs, sexual maturity begins to happen around age six to twelve months for both males and females,[1][128] although this can be delayed until up to two years old for some large breeds. This is the time at which female dogs will have their first estrous cycle. They will experience subsequent estrous cycles biannually, during which the body prepares for pregnancy. At the peak of the cycle, females will come into estrus, being mentally and physically receptive to copulation.[1] Because the ova survive and are capable of being fertilized for a week after ovulation, it is possible for a female to mate with more than one male.[1]

Dogs bear their litters roughly 56 to 72 days after fertilization,[1][129] with an average of 63 days, although the length of gestation can vary. An average litter consists of about six puppies,[130] though this number may vary widely based on the breed of dog. Toy dogs generally produce from one to four puppies in each litter, while much larger breeds may average as many as twelve.

Some dog breeds have acquired traits through selective breeding that interfere with reproduction. Male French Bulldogs, for instance, are incapable of mounting the female. For many dogs of this breed, the female must be artificially inseminated in order to reproduce.[131]


A feral dog from Sri Lanka nursing her four puppies.Neutering refers to the sterilization of animals, usually by removal of the male's testicles or the female's ovaries and uterus, in order to eliminate the ability to procreate and reduce sex drive. Because of the overpopulation of dogs in some countries, many animal control agencies, such as the American Society for the Prevention of Cruelty to Animals (ASPCA), advise that dogs not intended for further breeding should be neutered, so that they do not have undesired puppies that may have to later be euthanized.[132]

According to the Humane Society of the United States, 3–4 million dogs and cats are put down each year in the United States and many more are confined to cages in shelters because there are many more animals than there are homes. Spaying or castrating dogs helps keep overpopulation down.[133] Local humane societies, SPCAs, and other animal protection organizations urge people to neuter their pets and to adopt animals from shelters instead of purchasing them.

Neutering reduces problems caused by hypersexuality, especially in male dogs.[134] Spayed female dogs are less likely to develop some forms of cancer, affecting mammary glands, ovaries, and other reproductive organs.[135] However, neutering increases the risk of urinary incontinence in female dogs,[136] and prostate cancer in males,[137] as well as osteosarcoma, hemangiosarcoma, cruciate ligament rupture, obesity, and diabetes mellitus in either gender.[138]

Intelligence and behavior


Main article: Dog intelligence

The Border Collie is considered to be one of the most intelligent breeds.The domestic dog has a predisposition to exhibit a social intelligence that is uncommon in the animal world.[91] Dogs are capable of learning in a number of ways, such as through simple reinforcement (e.g. classical or operant conditioning) and by observation.[91]

Dogs go through a series of stages of cognitive development. As with humans, the understanding that objects not being actively perceived still remain in existence (called object permanence) is not present at birth. It develops as the young dog learns to interact intentionally with objects around it, at roughly 8 weeks of age.[91]

Puppies learn behaviors quickly by following examples set by experienced dogs.[91] This form of intelligence is not peculiar to those tasks dogs have been bred to perform, but can be generalized to myriad abstract problems. For example, Dachshund puppies who watched an experienced dog pull a cart by tugging on an attached piece of ribbon in order to get a reward from inside the cart learned the task fifteen times faster than those who were left to solve the problem on their own.[91][139] Dogs can also learn by mimicking human behaviors. In one study, puppies were presented with a box, and shown that when a handler pressed a lever, a ball would roll out of the box. The handler then allowed the puppy to play with the ball, making it an intrinsic reward. The pups were then allowed to interact with the box. Roughly three-quarters of the puppies subsequently touched the lever, and over half successfully released the ball, compared to only 6 percent in a control group that did not watch the human manipulate the lever.[140] Another study found that handing an object between experimenters who then used the object's name in a sentence successfully taught an observing dog each object's name, allowing the dog to subsequently retrieve the item.[141]

Dogs also demonstrate sophisticated social cognition by associating behavioral cues with abstract meanings.[91] One such class of social cognition involves the understanding that others are conscious agents. Research has shown that dogs are capable of interpreting subtle social cues, and appear to recognize when a human or dog's attention is focused on them. To test this, researchers devised a task in which a reward was hidden underneath one of two buckets. The experimenter then attempted to communicate with the dog to indicate the location of the reward by using a wide range of signals: tapping the bucket, pointing to the bucket, nodding to the bucket, or simply looking at the bucket.[142] The results showed that domestic dogs were better than chimpanzees, wolves, and human infants at this task, and even young puppies with limited exposure to humans performed well.[91]

Psychology research has shown that human faces are asymmetrical with the gaze instinctively moving to the right side of a face upon encountering other humans to obtain information about their emotions and state. Research at the University of Lincoln (2008) shows that dogs share this instinct when meeting a human being, and only when meeting a human being (i.e., not other animals or other dogs). As such they are the only non-primate species known to do so.[143][144]

Dr. Stanley Coren, an expert on dog psychology, states that these results demonstrated the social cognition of dogs can exceed that of even our closest genetic relatives, and that this capacity is a recent genetic acquisition which distinguishes the dog from its ancestor, the wolf.[91] Studies have also investigated whether dogs engaged in partnered play change their behavior depending on the attention-state of their partner.[145] Those studies showed that play signals were only sent when the dog was holding the attention of its partner. If the partner was distracted, the dog instead engaged in attention-getting behavior before sending a play signal.[145]

Dr. Coren has also argued that dogs demonstrate a sophisticated theory of mind by engaging in deception, which he supports with a number of anecdotes, including one example where a dog hid a stolen treat by sitting on it until the rightful owner of the treat left the room.[91] Although this could have been accidental, Coren suggests that the thief understood that the treat's owner would be unable to find the treat if it were out of view. Together, the empirical data and anecdotal evidence points to dogs possessing at least a limited form of theory of mind.[91][145]


Main article: Dog behavior

Further information: Category:Dog training and behavior

Although dogs have been the subject of a great deal of behaviorist psychology (e.g. Pavlov's dog), they do not enter the world with a psychological "blank slate".[91] Rather, dog behavior is affected by genetic factors as well as environmental factors.[91] Domestic dogs exhibit a number of behaviors and predispositions that were inherited from wolves.[91] The Gray Wolf is a social animal that has evolved a sophisticated means of communication and social structure. The domestic dog has inherited some of these predispositions, but many of the salient characteristics in dog behavior have been largely shaped by selective breeding by humans. Thus some of these characteristics, such as the dog's highly developed social cognition, are found only in primitive forms in grey wolves.[142]

The existence and nature of personality traits in dogs have been studied (15329 dogs of 164 different breeds) and five consistent and stable "narrow traits" identified, described as playfulness, curiosity/fearlessness, chase-proneness, sociability and aggressiveness. A further higher order axis for shyness–boldness was also identified.[146][147]

Differences from wolves

Some dogs, like this Tamaskan, look very much like wolves.Physical characteristics

Compared to equally sized wolves, dogs tend to have 20% smaller skulls, 30% smaller brains,[148] as well as proportionately smaller teeth than other canid species.[149] Dogs require fewer calories to function than wolves. Their diet of human refuse in antiquity made the large brains and jaw muscles needed for hunting unnecessary. It is thought by certain experts that the dog's limp ears are a result of atrophy of the jaw muscles.[149] The skin of domestic dogs tends to be thicker than that of wolves, with some Inuit tribes favoring the former for use as clothing due to its greater resistance to wear and tear in harsh weather.[149] The paws of a dog are half the size of those of a wolf, and their tails tend to curl upwards, another trait not found in wolves.[150]


Dogs tend to be poorer than wolves at observational learning, being more responsive to instrumental conditioning.[149] Feral dogs show little of the complex social structure or dominance hierarchy present in wolf packs. For dogs, other members of their kind are of no help in locating food items, and are more like competitors.[149] Feral dogs are primarily scavengers, with studies showing that unlike their wild cousins, they are poor ungulate hunters, having little impact on wildlife populations where they are sympatric. However, feral dogs have been reported to be effective hunters of reptiles in the Galápagos Islands,[151] and free ranging pet dogs are more prone to predatory behavior toward wild animals.

Despite common belief, domestic dogs can be monogamous.[152] Breeding in feral packs can be, but does not have to be restricted to a dominant alpha pair (despite common belief, such things also occur in wolf packs).[153] Male dogs are unusual among canids by the fact that they mostly seem to play no role in raising their puppies, and do not kill the young of other females to increase their own reproductive success.[151] Some sources say that dogs differ from wolves and most other large canid species by the fact that they do not regurgitate food for their young, nor the young of other dogs in the same territory.[149] However, this difference was not observed in all domestic dogs. Regurgitating of food by the females for the young as well as care for the young by the males has been observed in domestic dogs, dingos as well as in other feral or semi-feral dogs. Regurgitating of food by the females and direct choosing of only one mate has been observed even in those semi-feral dogs of direct domestic dog ancestry. Also regurgitating of food by males has been observed in free-ranging domestic dogs.[152][154]


Dogs display much greater tractability than tame wolves, and are generally much more responsive to coercive techniques involving fear, aversive stimuli, and force than wolves, which are most responsive toward positive conditioning and rewards.[155] Unlike tame wolves, dogs tend to respond more to voice than hand signals.

Saturday, August 14, 2010

Independence Day (India)

India's Independence Day is celebrated on 15 August to commemorate its independence from British rule and its birth as a sovereign nation on that day in 1947.[1] The day is a national holiday in India. All over the country, flag-hoisting ceremonies are conducted by the local administration in attendance. The main event takes place in New Delhi, where the Prime Minister hoists the national flag at the Red Fort and delivers a nationally televised speech from its ramparts. In his speech, he highlights the achievements of his government during the past year, raises important issues and gives a call for further development. The Prime Minister also pays his tribute to leaders of the freedom struggle. U.S. also recognizes this day as India Day. [2][3]

[edit] Celebrations

The Prime Minister of India hoists the Indian flag on the ramparts of the historical site, Red Fort, Delhi, on August 15. 15 August is a national holiday in India. Government Offices are lit up. Flag hoisting ceremonies and cultural programs take place in all the state capitals. In the cities around the country the national flag is hoisted by politicians in their constituencies. In various private organisations the flag hoisting is carried out by a senior official of that organisation.All over the country, flags are given out to citizens who wear them proudly to show their patriotism towards India. Schools and colleges around the country organise flag hoisting ceremonies and various cultural events within their premises, where younger children in costume do impersonations of their favourite characters of the Independence era.They also have a parade. Families and friends get together for lunch or dinner, or for an outing. Housing colonies, cultural centres, clubs and societies hold entertainment programs and competitions, usually based on the Independence Day theme. Most national and regional television channels screen old and new film classics with patriotic themes on Independence Day.

Monday, August 9, 2010

Audio Video Interleave

Audio Video Interleave

Audio Video Interleave, known by its acronym AVI, is a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows technology. AVI files can contain both audio and video data in a file container that allows synchronous audio-with-video playback. Like the DVD video format, AVI files support multiple streaming audio and video, although these features are seldom used. Most AVI files also use the file format extensions developed by the Matrox OpenDML group in February 1996. These files are supported by Microsoft, and are unofficially called "AVI 2.0".


AVI is a derivative of the Resource Interchange File Format (RIFF), which divides a file's data into blocks, or "chunks." Each "chunk" is identified by a FourCC tag. An AVI file takes the form of a single chunk in a RIFF formatted file, which is then subdivided into two mandatory "chunks" and one optional "chunk".

The first sub-chunk is identified by the "hdrl" tag. This sub-chunk is the file header and contains metadata about the video, such as its width, height and frame rate. The second sub-chunk is identified by the "movi" tag. This chunk contains the actual audio/visual data that make up the AVI movie. The third optional sub-chunk is identified by the "idx1" tag which indexes the offsets of the data chunks within the file.

By way of the RIFF format, the audio/visual data contained in the "movi" chunk can be encoded or decoded by software called a codec, which is an abbreviation for (en)coder/decoder. Upon creation of the file, the codec translates between raw data and the (compressed) data format used inside the chunk. An AVI file may carry audio/visual data inside the chunks in virtually any compression scheme, including Full Frame (Uncompressed), Intel Real Time (Indeo), Cinepak, Motion JPEG, Editable MPEG, VDOWave, ClearVideo / RealVideo, QPEG, and MPEG-4 Video.

[edit] Metadata

As a derivative of the Resource Interchange File Format (RIFF), AVI files can be tagged with metadata in the INFO chunk. In addtion, AVI files can embed Extensible Metadata Platform (XMP).

[edit] Continued use

Since its introduction in the early 90s, new computer video techniques have been introduced which the original AVI specification did not anticipate.

AVI does not provide a standardised way to encode aspect ratio information, with the result that players cannot select the right one automatically (though it may be possible to do so manually).[2]

There are several competing approaches to including timecode in AVI files, which affects usability of the format in film and television postproduction (although it is widely used). An equivalent of the Broadcast Wave extensions, designed to standardise postproduction metadata for wave audio files, has not emerged.

AVI is not intended to contain variable frame rate material. Workarounds for this limitation increase overhead dramatically.

AVI was not intended to contain video using any compression technique which requires access to future video frame data beyond the current frame. Approaches exist to support modern video compression techniques (e.g. MPEG-4) which rely on this functionality, although this is beyond the intent of the original specification and may cause problems with playback software which does not anticipate this use.

AVI cannot contain some specific types of VBR data (such as MP3 audio at sample rates below 32KHz) reliably.

Overhead for AVI files at the resolutions and frame rates normally used to encode feature films is about 5 MB per hour of video, the significance of which varies with the application.

More recent container formats (such as Matroska, Ogg and MP4) solve all these problems, although software is freely available to both create and correctly replay AVI files which use these more recent techniques.

[edit] DV AVI

DV AVI (aka DV-AVI) is a type of AVI file where the video has been compressed to conform with DV standards. There are two types of DV-AVI files:

Type 1: The multiplexed Audio-Video is kept in its original multiplexing and saved together into the Video section of the AVI file

Does not waste much space (audio is saved uncompressed, but even uncompressed audio is tiny compared to the video part of DV), but Windows applications based on the VfW API do not support it.

Type 2: Like type 1, but audio is also saved as an additional audio stream into the file.

Supported by VfW applications, at the price of a small increase in file size.

Type 1 is actually the newer of the two types. Microsoft made the "type" designations, and decided to name their older VfW-compatible version "Type 2", which only furthered confusion about the two types. In the late 1990s through early 2000s, most professional-level DV software, including non-linear editing programs, only supported Type 1. One notable exception was Adobe Premiere, which only supported Type 2. High-end FireWire controllers usually captured to Type 1 only, while "consumer" level controllers usually captured to Type 2 only. Software is and was available for converting Type 1 AVIs to Type 2, and vice-versa, but this is a time-consuming process.

Many current FireWire controllers still only capture to one or the other type. However, almost all current DV software supports both Type 1 and Type 2 editing and rendering, including Adobe Premiere. Thus, many of today's users are unaware of the fact that there are two types of DV AVI files. In any event, the debate continues as to which – Type 1 or Type 2 – if either, is better.

When we cook something on gas.

When we cook something on gas, the steam comes out. But when we turn off the gas, the steam increases. Why this happens.

Thursday, August 5, 2010


Summer is the warmest of the four temperate seasons, between spring and autumn. It is marked by the longest days and shortest nights. The seasons start on different dates in different cultures based on astronomy and regional meteorology. However, when it is summer in the southern hemisphere it is winter in the northern hemisphere, and vice versa. In areas of the tropics and subtropics, the wet season occurs during the summer. Tropical cyclones develop and roam the tropical and subtropical oceans during the summer. In the interior of continents, thunderstorms are most likely to produce hail during the afternoon and evening. Schools and universities have a summer break to take advantage of the warmer weather and longer days.


From an astronomical view, the equinoxes and solstices would be the middle of the respective seasons, but a variable seasonal lag means that the meteorological start of the season, which is based on average temperature patterns, occurs several weeks later than the start of the astronomical season.[1] According to meteorologists, summer extends for the whole months of June, July and August in the northern hemisphere and the whole months of December, January and February in the southern hemisphere.[2] This meteorological definition of summer also aligns with the commonly viewed notion of summer as the season with the longest (and warmest) days of the year, in which daylight predominates. From the astronomical perspective, days continue to lengthen from equinox to solstice and summer days progressively shorten after the solstice, so meteorological summer encompasses the build-up to the longest day and a diminishing thereafter, with summer having many more hours of daylight than spring.

The meteorological reckoning of seasons is used in Austria, Denmark and the former USSR; it is also used by many in the United Kingdom, where summer is thought of as extending from mid-May to mid-August. The definition based on equinox to solstice is more frequently used in the United States where a temperature lag of up to half a season is common[3].

Summer in Fethiye, Turkey.Elsewhere, however, Solstices and equinoxes are taken to mark the mid-points, not the beginnings, of the seasons. In Chinese astronomy, for example, summer starts on or around 5 May, with the jiéqì (solar term) known as lìxià (立夏), i.e. "establishment of summer", and it ends on or around 6 August. An example of Western usage would be William Shakespeare's A Midsummer Night's Dream, where the play takes place over the shortest night of the year, which is the summer solstice.

In Ireland, the summer months according to the national meteorological service, Met Eireann, are June, July and August. However, according to the Irish Calendar summer begins 1 May and ends 1 August. School textbooks in Ireland follow the cultural norm of summer commencing on 1 May rather than the meteorological definition of 1 June.

In southern and southeast Asia, where the monsoon occurs, summer is more generally defined as lasting from March to May/early June, their warmest time of the year, ending with the onset of the monsoon rains.[citation needed]

In the United States, summer is often fixed as the period from the summer solstice (June 20 or 21, depending on the year) to the fall equinox (September 22 or 23, again depending on the year).[4][5][6][7] Unofficially, the U.S. summer season is commonly regarded as beginning on Memorial Day weekend and ending on Labor Day weekend. Likewise, another set of pop-cultural reference points for summer in the USA is the time when elementary and secondary schools close down for the "summer vacation". This period usually lasts from around early to mid June until around late August to early September, depending on where the school is located.

[edit] Weather

Wet season thunderstorm at night in Darwin, Australia.See also: Hail, Tropical cyclone, and Wet season

Summer is traditionally associated with hot dry weather, but this does not occur in all regions. The wet season occurs during summer across many parts of the tropics and subtropics. Where the wet season is associated with a seasonal shift in the prevailing winds, it is known as a monsoon.[8] The wet season is the main period of vegetation growth within the savanna climate regime.[9] However, this also means that wet season is a time for food shortages before crops reach their full maturity.[10] This causes seasonal weight changes for people in developing countries, with a drop occurring during the wet season until the time of the first harvest, when weights rebound.[11] Malaria incidence increases during periods of high temperature and heavy rainfall.[12]

The onset of the rainy season signals the departure of the Monarch butterfly from Mexico.[13] Tropical species of butterflies show larger dot markings on their wings to fend off possible predators and are more active during the wet season than the dry season.[14] Within the tropics and warmer areas of the subtropics, decreased salinity of near shore wetlands due to the rains causes an increase in crocodile nesting.[15] Other species, such as the arroyo toad, spawn within the couple months after the seasonal rains.[16] Armadillos and rattlesnakes seek higher ground.[17]

Image of Hurricane Lester from late August 1992.In the Northern Atlantic Ocean, a distinct tropical cyclone season occurs from 1 June to 30 November, sharply peaking from late August through September.[18] The statistical peak of the Atlantic hurricane season is 10 September. The Northeast Pacific Ocean has a broader period of activity, but in a similar time frame to the Atlantic.[19] The Northwest Pacific sees tropical cyclones year-round, with a minimum in February and March and a peak in early September. In the North Indian basin, storms are most common from April to December, with peaks in May and November.[18] In the Southern Hemisphere, the tropical cyclone year begins on 1 July and runs all year round and encompasses the tropical cyclone seasons which run from 1 November until the end of April with peaks in mid-February to early March.[18][20]

Across interior North America, cumulonimbus clouds produce hail between the months of March and October during the afternoon and evening hours, with the bulk of the occurrences from May through September. Cheyenne, Wyoming is North America's most hail-prone city with an average of nine to ten hailstorms per season.[21]

[edit] Construction

In higher latitude locations, summer is the time for road resurfacing, as winter ice and snow leaves potholes behind in the pavement due to the expansion and contraction of ice and snow during the winter months. Construction jobs tend to have minimum temperature requirements in order for work to be accomplished, such as the laying of concrete. This is because materials like concrete take increasingly longer to dry within cold temperature regimes. Also, working within warmer weather regimes is done to prevent expansion of ice within the new material, which decreases its potential strength and integrity.[22]

[edit] School break

In most countries children are out of school during this time of year for summer holidays, although dates vary. In the Northern hemisphere, some begin as early as mid-May, although in England and Wales, school ends in mid- to late July. In the Southern hemisphere, school holiday dates include the major holidays of Christmas and New Year's Day. Summer school holidays in Australia begin a few weeks before Christmas and end in late January to mid-February, with the dates varying in different states.



A cloud is a visible mass of droplets of water or frozen crystals suspended in the atmosphere above the surface of the Earth or another planetary body. A cloud is also a visible mass attracted by gravity, such as masses of material in space called interstellar clouds and nebulae. Clouds are studied in the nephology or cloud physics branch of meteorology.

On Earth the condensing substance is typically water vapor, which forms small droplets or ice crystals, typically 0.01 mm (0.00039 in) in diameter. When surrounded by billions of other droplets or crystals they become visible as clouds. Dense deep clouds exhibit a high reflectance (70% to 95%) throughout the visible range of wavelengths. They thus appear white, at least from the top. Cloud droplets tend to scatter light efficiently, so that the intensity of the solar radiation decreases with depth into the gases, hence the gray or even sometimes dark appearance at the cloud base. Thin clouds may appear to have acquired the color of their environment or background and clouds illuminated by non-white light, such as during sunrise or sunset, may appear colored accordingly. Clouds look darker in the near-infrared because water absorbs solar radiation at those wavelengths.

A cumulus cloudscape over Swifts Creek, Victoria, AustraliaCloud types or genera are grouped into three general categories: cirriform (wispy), stratiform (layered in sheets) and convective or cumuliform (heaped, rolled and/or rippled). These designations distinguish a cloud's physical structure and process of formation. All weather-related cloud types form in the troposphere, the lowest major layer of the earth's atmosphere. The individual genus types result from the categories being cross-classified by height range within the troposphere. This is determined by the base height of the cloud, not the cloud top, and base height ranges may vary depending on the geographical zone. Each cloud genus is divided into species and/or varieties determined by more specific aspects of it structure and/or process of formation in any particular situation. All Cirrus clouds are classified as high and thus constitute a single genus. Cumulus and stratus clouds in the high altitude range carry the prefix 'cirro', while similar genera in the middle range are prefixed by 'alto'. Any cumuliform or stratiform genus in the low or low to middle range either has no prefix or carries one that refers to a characteristic other than altitude. A vertically developed cloud genus or species typically occupies all altitude ranges and therefore has no height related prefix. This system was proposed in 1802, when it was presented to the Askesian Society by Luke Howard.

A sky of cirrus clouds.[edit] High clouds (Family A)

High clouds will form between 10,000 and 25,000 ft (3,000 and 8,000 m) in the polar regions, 16,500 and 40,000 ft (5,000 and 12,000 m) in the temperate regions and 20,000 and 60,000 ft (6,000 and 18,000 m) in the tropical region.[1]

Clouds in Family A include:

Genus Cirrus (Ci)

Genus Cirrocumulus (Cc)

Genus Cirrostratus (Cs)

[edit] Middle clouds (Family B)

Middle clouds tend to form at 6,500 ft (2,000 m) but may form at heights up to 13,000 ft (4,000 m), 23,000 ft (7,000 m) or 25,000 ft (8,000 m) depending on the region. Generally the warmer the climate, the higher the cloud base. Nimbostratus clouds are sometimes included with the middle clouds.[1] The World Meterological Organization classifies Nimbostratus as a middle cloud that can thicken down into the low height range during precipitation.

Clouds in Family B include:

Genus Altocumulus (Ac)

Genus Altostratus (As)

[edit] Low clouds (Family C1)

Stratocumulus clouds, between Cumulus in the foreground and backgroundThese are found from near surface up to 6,500 ft (2,000 m)[1] and include the stratus (dense and grey). When stratus clouds contact the ground, they are called fog.

Clouds in Family C1 include:

Genus Stratocumulus (Sc)

Genus Stratus (St)

[edit] Low to middle clouds (Family C2)

These clouds can be based anywhere from near surface to about 10,000 ft (3,000 m). Cumulus usually forms in the low altitude range but bases may rise into the lower part of the middle range during conditions of very low relative humidity. Nimbostratus normally forms from altostratus in the middle altitude range but the base may subside into the low range during precipitaion.

Clouds in Family C2 include:

Genus Cumulus[2] (Cu)

Species Cumulus humilis (Cu hum)

Species Cumulus mediocris (Cu med)

Genus Nimbostratus (Ns)

[edit] Vertical clouds (Family D)

A typical anvil shaped Cumulonimbus incusThese clouds can have strong up-currents, rise far above their bases and form at many heights.

Clouds in Family D include:

Genus Cumulonimbus (associated with heavy precipitation and thunderstorms) (Cb)

Species Cumulonimbus calvus (Cb cal)

Species Cumulonimbus capillatus (Cb cap)

Variety Cumulonimbus incus (Cb inc)

Variety Cumulonimbus with mammatus (Cb mam) Official WMO term Cumulonimbus mamma.

Genus Cumulus (Cu)[3][4]

Species Cumulus congestus (TCu)

Pyrocumulus (No official abbreviation, not recognised by WMO as a distinct genus or species.)

[edit] Other clouds

A few clouds can be found above the troposphere; these include noctilucent and polar stratospheric clouds (or nacreous clouds), which occur in the mesosphere and stratosphere respectively.

Some clouds form as a consequence of interactions with specific geographical features. Perhaps the strangest geographically specific cloud in the world is Morning Glory, a rolling cylindrical cloud which appears unpredictably over the Gulf of Carpentaria in Northern Australia. Associated with a powerful "ripple" in the atmosphere, the cloud may be "surfed" in glider aircraft.

[edit] Cloud fields

A cloud field is simply a group of clouds but sometimes cloud fields can take on certain shapes that have their own characteristics and are specially classified. Stratocumulus clouds can often be found in the following forms:

Actinoform, which resembles a leaf or a spoked wheel.

Closed cell, which is cloudy in the center and clear on the edges, similar to a filled honeycomb.

Open cell, which resembles a honeycomb, with clouds around the edges and clear, open space in the middle.

[edit] Colors

Cloud iridescence occurring in clouds

Sunset reflecting shades of grey and pink in clouds.The color of a cloud, as seen from the Earth, tells much about what is going on inside the cloud. Clouds form because warm air tends to absorb water vapor, which is lighter than air, thus helping the mixture to rise. As it rises the air containing it cools and the vapor tends to condense out of the air as micro-droplets. These tiny particles of water are densely packed and sunlight cannot penetrate far into the cloud before it is reflected out, giving a cloud its characteristic white color. As a cloud matures, the dense water droplets may combine to produce larger droplets, which may combine to form droplets large enough to fall as rain. By this process of accumulation, the space between droplets becomes increasingly larger, permitting light to penetrate farther into the cloud. If the cloud is sufficiently large and the droplets within are spaced far enough apart, it may be that a percentage of the light which enters the cloud is not reflected back out before it is absorbed. A simple example of this is being able to see farther in heavy rain than in heavy fog. This process of reflection/absorption is what causes the range of cloud color from white to black. For the same reason, the undersides of large clouds and heavy overcasts can appear as various degrees of grey shades, depending on how much light is being reflected or transmitted back to the observer.

Other colors occur naturally in clouds. Bluish-grey is the result of light scattering within the cloud. In the visible spectrum, blue and green are at the short end of light's visible wavelengths, while red and yellow are at the long end. The short rays are more easily scattered by water droplets, and the long rays are more likely to be absorbed. The bluish color is evidence that such scattering is being produced by rain-sized droplets in the cloud.

A greenish tinge to a cloud is produced when sunlight is scattered by ice. A cumulonimbus cloud emitting green is an imminent sign of heavy rain, hail, strong winds and possible tornadoes.

Yellowish clouds are rare but may occur in the late spring through early fall months during forest fire season. The yellow color is due to the presence of pollutants in the smoke.

Red, orange and pink clouds occur almost entirely at sunrise/sunset and are the result of the scattering of sunlight by the atmosphere. The clouds do not become that color; they are reflecting long and unscattered rays of sunlight, which are predominant at those hours. The effect is much like if one were to shine a red spotlight on a white sheet. In combination with large, mature thunderheads this can produce blood-red clouds.

[edit] Clouds and climate

Global cloud cover, averaged over the month of October, 2009. The outlines of the continents can often be traced through observations of clouds alone, with the sharpest outlines where very dry land is surrounded by ocean. NASA composite satellite image; larger image available here.See also: Cloud cover and Cloud feedback

Understanding the role of clouds in regulating both weather and climate is at an early stage, and remains a critical unknown factor in predicting the extent of global warming.[citation needed]

[edit] Global brightening

New research indicates a global brightening trend.[5]

Global brightening is caused by decreased amounts of particulate matter in the atmosphere, leaving less surface area for condensation to occur. Less condensation in the atmosphere and more evaporation from increasing amounts of sunlight striking the surfaces of water causes more moisture to build in the air, creating fewer but more dense clouds.

[edit] Bacteria in clouds

Bacteria that live in clouds may have evolved the ability to promote rainstorms as a way to disperse themselves. These microbes—called ice nucleators—are found in rain, snow, and hail throughout the world, according to Brent Christner, a microbiologist at Louisiana State University. These bacteria may be part of a constant feedback between terrestrial ecosystems and clouds. They may rely on the rainfall to spread to new habitats, much as plants rely on windblown pollen grains, Christner said. [6]

[edit] Other planets

Main article: Extraterrestrial atmospheres

Within our Solar System, any planet or moon with an atmosphere also has clouds. Venus's clouds are composed of sulfuric acid droplets. Mars has high, thin clouds of water ice. Both Jupiter and Saturn have an outer cloud deck composed of ammonia clouds, an intermediate deck of ammonium hydrosulfide clouds and an inner deck of water clouds. Uranus and Neptune have cloudy atmospheres dominated by methane gas.

Saturn's moon Titan has clouds believed to be composed largely of droplets of liquid methane. The Cassini–Huygens Saturn mission uncovered evidence of a fluid cycle on Titan, including lakes near the poles and fluvial channels on the surface of the moon.

Friendship Day

Friendship Day

Friendship Day History

History of Friendship Day in US

Considering the valuable role friends play in our life it was deemed to fit to have a day dedicated to friends and friendship. The United States Congress, in 1935, proclaimed first Sunday of August as the National Friendship Day. Since then, celebration of National Friendship Day became an annual event. The noble idea of honoring the beautiful relationship of friendship caught on with the people and soon Friendship Day became a hugely popular festival.

Following the popularity and success of Friendship Day in US, several other countries adopted the tradition of dedicating a day to friends. Today, Friendship Day is enthusiastically celebrated by several countries across the world including India.

In 1997, the United Nations named Winnie - the Pooh as the world's Ambassador of Friendship.

Importance of Friendship in Bible

The Bible, the primary text of the western civilization, reflects upon friendship as the bond that forms the foundation to human faith, trust and companionship. Following verses from the bible aptly portray the importance of friends:

"Ask and it will be given to you; seek and you will find; knock and the door will be opened to you.”

Matthew 7:7

“Greater love hath no man than this that a man lay down his life for his friends.”

John 15:13-15

Besides, there are several tales from the Old Testament and the New Testament about the value of friendship and how true friendship is a treasure to unearth. A noticeable point is that, both the versions make a difference between the two broad meanings of friendship- one is a mere acquaintance, the other is a more affectionate relation.

In the Old Testament, Abraham is called the “friend of God” because of the intimacy of his relations. God speaks to Moses face to face “as a man…unto his friend” (Ex 33:11). The romantic friendship of Ruth and Naomi, the devotion of the subordinate Hushai for David, or the mutual relation between David and Jonathan - the Old Testament is replete with these interesting tales of friends and friendship.

In the New Testament, the relationship between Jesus and his disciples clearly depicts how human friendship can constantly grow. From being teacher and disciple, to lord and servant their relationship finally grew to an unparalleled friendship.

Importance of Friendship in Mahabharata

In the famous Hindu epic ‘Mahabharata’, Lord Krishna demonstrates the many colors of friendship - affection, romance, brotherhood, protection, guidance, intimacy and even teasing. Friendship is all about these and much more.

Tribute to a Friend

Friendship Day is celebrated in honor of friends who make our lives so special and help us give a meaningful direction to our lives. On Friendship Day people must pay sincerest tribute to friends, both old and new, and appreciate the important role played by them in shaping their lives.

Significance of Friends

True friendship is about putting your feet up and knowing that someone is there to bail you out when the world might walk out on you. Besides, as a support system in today's hectic world, friends are the most reliable sources for social, intellectual and creative stimulations.

In the present fast pace age of nuclear families where people have little time to spend with each other, friends have become indispensable. Then there are times when we find it tough to discuss matters with our family members or even with our spouse, it is on occasions such as these that friends come to our support. They guide us and become our pillar of strength when we need them most. And the best part is we don't really need to put things in words when communicating issues to our best friends. Most often friends understand us, just by looking at us or hearing our voice. This heart-to-heart bonding is what makes friendship so exclusive, setting it apart from all other relationships.

Significance of Expressing Love to Friends

Howsoever strong a relationship maybe, it constantly needs to be nurtured with love and care. We must therefore never lose an opportunity to express our feelings and the warmth we may be experiencing for our friends. We may do this by sending flowers, a heartfelt card or a thoughtful gift. We may also do this by being together with a friend in times of joy or sorrow. The idea is to keep expressing our unconditional love and support to our dearest friend let the friendship evolve.

Significance of Friendship Day

At times we get so busy in our daily lives that we start taking our friends for granted. It is the annual celebration of Friendship Day that reminds us that we must cherish the presence of friends in our lives and acknowledge with love the important role they play in our lives. One must therefore celebrate friendship on Friendship Day to the fullest and let their friendship soar to newer heights.

Friendship Day in India

Friendship Day has come to be celebrated in a big way in India. The noble idea of honoring friends and friendship has really caught on with the youth in India and one can see the festival being enthusiastically celebrated by the youth especially, students.

Day Dedicated to Friends

In tune with the spirit of the occasion, people dedicate Friendship Day festival to their best friends. Most choose to celebrate the entire day in the loving company of their dearest friends. Recollecting sweet memories of the time spent together and catching up with their lives over a cup of coffee is the idea of ideal Friendship Day celebration for many.

Friends separated by geographical distances, call up their friends to express love and warmth for each other and to wish a "Happy Friendship Day". With more and more people getting hooked to the net, many people also choose to chat with their friends with the help of Internet. Sending SMS and Friendship Day e-cards is another popular way of greetings friends.

Friendship Day Celebrations in Schools and Colleges

Friendship Day celebrations are particularly marked in schools and colleges in India. Euphoria of the day sets in days before the festival as everybody gets excited to wish their best friends in their own special way. Children make Friendship Day Cards or other special gift to thank their friends for their wonderful presence in their life. Exchange of Friendship Bands is the other most prominent feature of Friendship Day celebrations. Friends vie with each other as to who gets the most stylish band or who gets the maximum number of bands.

In several colleges, special programs are also organized to mark the occasion. Most of these programs and events intend to give youth an opportunity to dance and sing with friends and have a good time.

Friendship Day Parties

Following their counterparts in the west, youth in India too mark Friendship Day by participating in Friendship Day parties or organizing bashes for their friends. Major crowd for Friendship Day can be seen in discotheques and pubs where people dance with friends on fast pace music and cherish the loving company of their pals. Such parties also give youth a chance to make new friends and widen their friendship circle. At present such bashes are more popular in metros and other big cities, however, youth in small towns too are warming up to the idea of partying on Friendship Day.

Commercialization of Friendship Day

Just as in US and several other countries, Friendship Day has been commercialized to a great extent in India. Days before the festival, gift marketers run an extensive campaign to lure the people to buy cards and gifts for their friends. Restaurateurs too try to entice people by offering special discounts or holding bashes. Several people criticize such excessive campaigning. They feel commercialization has marred to the idea behind observing Friendship Day and has turned it into a mere formality. Some people however feel that advertising campaign has helped to generate awareness about Friendship Day festival and the idea of having a day dedicated to friends.

Friendship Day Celebration Ideas

Friendship Day is the perfect occasion to let your friends know how much they are needed and loved. The day calls for celebrations and enjoyment in the company of closed pals and chums!! The best way to celebrate Friendship Day would be to spend the day in a way your friendship group enjoys the most. In case you want to be creative and do something different to mark this significant day, here are some Friendship Day celebration ideas just for you. So go ahead and have a fabulous and over-the-top Friendship Day celebration

Organize a Friendship Day Party

The most special way to celebrate Friendship Day would be hold a party for your new friends and old and have a blast. However, this idea needs a little planning and effort as you need to decide where to party, how to party, what to include in menu, what to play on the jukebox so on and so forth. Once that's done, call up your buddies and just have your fling !

Tips for Party Planning

· Design a special invite for friends. You may include cartoons, jokes and nice quotes to set the mood of the party and tempt your friends to come over.

· Inform your friends about the nature of the party whether it will be a day party or over-night party. Picnicking would be yet another sprightly thought for your Friendship Day party.

· Once the kind of your Friendship Day party is fixed, decide on the menu. In case of a picnic plan for cooking with your friends. It will be great fun.

· You may also plan out indoor or outdoor game session with your friends.

· Also incorporate a music session with your friends. You may chose to play the music yourself, list to music or dance on it depending on the preference of your friends club.

· Keep the camera ready and capture the precious moments on your Friendship Day party.

· Bind your buds in the friendship bond with the friendship bands. You can make them yourself or pick them up from the stores.

More Friendship Day Celebration Ideas

Here are some ideas of celebrating Friendship Day. The idea is to spend spend quality time with your friends and have a great time.

Camping Out

Camp out can be your chance to check out on your favorite sets of outdoor sports-trekking, beach volleyball, basketball, baseball, rugby, swimming, surfing and more in the company of your best pals. Just choose a sport which your group enjoys and take a dive into a zesty, action-packed Friendship Day celebration !

Sharing Thoughts and Views

For many the best kind of Friendship Day celebration is perhaps a heart-to-heart talk with a soul mate. Sharing everything that has mattered to you and your friend for so long and for so many days and catching up with each others life is a relaxing way of celebrating Friendship Day.

Recollect Sweet Memories

A great way to celebrate Friendship Day in a memorable way would be make an album of your most intimate and special moments spent together. This can also be the most touching Friendship Day activity for you and your friend as it will help you to rewind and relive your time-tested bonding.

Make a Poster

A great idea to celebrate friendship in a creative manner would be to create a poster on Friendship Day. For instance you may paint your name and your friend's name on it creatively and revel in the joy when your friend flashes that million-dollar smile.

Friendship Day Gift Ideas

Friendship Day Gifts play a significant role in strengthening the relationship you share with your loved ones. Friendship Gifts must therefore be selected with love and care. A friendship present need not be precious and expensive ones but it must definitely exude love and warmth you feel for your friend. In case you are finding it hard to decide a perfect Friendship Gift for your best friend, here some popular Friendship Day Gift ideas just for you.

Friendship Bands

Friendship Band is one of the most popular Friendship Gift. Many colorful friendship bands hit the stores much ahead of Friendship Day. Instead of the conventional wristbands, one can go for the friendship bracelets which come in attractive designs for both boys and girls. This way your Friendship Day can stay longer with your friends besides it works as token of your love.


Fresh Flowers are the best and the easiest way to convey emotions and hence they make a wonderful gift for friends. If you are invited for a Friendship Day do, carry an attractive bouquet of pretty flowers for that heart touching impact. Ideally, you must choose your friends favorite flower. In case your friend does not have a specific choice, you may safely go in for Yellow Roses as these are officially recognized as the Friendship Day flowers.

Show Pieces

Cute and attractive show pieces are another extremely popular Friendship Day Gift. Depending upon your choice one can go in for glass, metals, wood, paper mache or crystal show pieces. Besides, making a delightful Friendship Day Gift, decorative pieces help to create beautiful memories.


Chocolates makes a yummy and delicious Friendship Day gift for foodies. Go in for a hamper of your friend's favorite chocolate to bring that million dollar smile on his/her face. A zestful idea would be to make a decorated friendship basket consisting of your friend's favorite gift items like chocolates, candy, cookies, a bunch of flowers, etc.

Soft Toys

Soft Toys make a cute Friendship gift. They are especially appreciated by girls who love to decorate their rooms with loads of soft toys and animals gifted by their loved ones. Go in for your friends favorite cartoon character to leave a lasting impression.

Photo Frames and Photo Albums

Photo frames and photo albums are a much sought after Friendship Day Gift. You may place a picture of you along with your friend or pictures of good time spend together to create beautiful memories.

Books, CDs

Books make a thoughtful Friendship Gift idea for friends fond of reading. But it is important to keep in mind the choice of your friend while selecting the book. Generally, you may give books of quotes or inspirational books.

Alternatively, you may gift music cassettes or CDs to friends fond of music. You may also give personalized CD by recording your friends favorite songs or songs that both of you enjoy. Games CDs are also a popular Friendship Day gift these days.


Stationery items like pens, diaries, letter or writing pad, planner, organizer etc make a wonderful Friendship Gift. Besides, one can gift utility items like watch, key rings, pen stand, telephone index, electronic notebook and so forth.

When is Friendship Day?

Celebrate Friendship Day 2010 on August 1, Sunday

Human beings are social creatures and have always valued the importance of friends in their lives. To celebrate this noble feeling it was deemed fit to have a day dedicated to friends and friendship. Accordingly, first Sunday of August was declared as a holiday in US in honor of friends by a Proclamation made by US Congress in 1935. Since then, World Friendship Day is being celebrated every year on the first Sunday in the month of August.

This beautiful idea of celebrating Friendship Day was joyfully accepted by several other countries across the world. And today, many countries including India, celebrate the first Sunday of August as Friendship Day every year. Celebrating Friendship Day in a traditional manner, people meet their friends and exchange cards and flowers to honor their friends. Lot many social and cultural organization too celebrate the occasion and mark Friendship Day by hosting programs and get together.

It may be noted that some associations celebrate Friendship Day in an entirely different time of the year and with different customs. For instance,

· National Friendship Day is on the first Sunday in August.

· Women's Friendship Day is on the third Sunday in August

· International Friendship Month is February

· Old Friends, New Friends Week is the third week of May

However, what is remarkably same is the idea behind the celebration of the day. Everywhere, people express love for their friends and cherish their presence in life.